A method for authorizing a user in order to obtain access to a restricted area has become known from the disclosure document WO 2010/000276 A1. Biometric data of the user are thereby detected and compared with stored data. A corresponding authorization for the user is subsequently transmitted to a wireless operator device and, via this operator device, to a control unit that serves to administer access to the restricted area.
In addition to this, nowadays there are a variety of mobile end devices, e.g., smartphones and other handheld operator devices, on which applications run that may connect with field devices in order to configure these or read out diagnostic information. These operator devices, or the applications on them, have security procedures in order to establish a secure connection with the field device.
Current security procedures for access control occasionally require complicated and time-consuming inputs by the user in order to achieve access to the field device.
Other methods that are used nowadays use keys for authentication, but these do not also incorporate information from the environment of the field device or of the operator device, for example, with regard to the user. However, the physical proximity between authorized user and operator device is of crucial relevance in industrial facilities.